Rabbit immunity a new threat to population control

Just as Australia begins to curb rabbit populations by introducing specific rabbit diseases, comes news of a genetically engineered vaccine which can provide them with immunity.

New Scientist reports that Spanish researchers have produced a genetically modified vaccine which protects rabbits against myxomatosis and rabbit haemorrhagic disease (RHD).

The research, published in the journal Vaccine shows that when rabbits become infected with the virus, a weakened form of myxomatosis, they become immunised. If they pass the virus on to a second rabbit, it too will become immune to the diseases. The concern is that immunity could spread rapidly through rabbit populations, which live close together in large communal burrows.

But the Spanish researchers claim the virus won't spread because it can not replicate properly. They said tests show the virus is safe, and are now running trials with live rabbits on an island.

Australian scientists have expressed concern should the virus ever be released or escape here. Brian Cooke of the CSIRO told New Scientist he was worried that the virus might behave differently or regain the ability to replicate once it got out.

"This self-propagating vaccine is not a development that sits easily with rabbit control in Australia," he said.

Spain by contrast is struggling to maintain rabbit numbers. Myxomatosis and RHD have taken a big toll and the hunting industry, which part funded the research, wants to see numbers recovered.

Meanwhile Spain is just as fearful a new rabbit-killing virus developed last year by Australian researchers could get into Spain.